That’s what I love about it, a list of aftermarket for a kit all in one place and often links to reviews for them.
I do use it to keep track of my stash, only kits ( for paint I use the excellent app Hobby Color Converter), and to create projects and keeping track of them. The only down side I could find is that it isn’t easy to keep track of kits (specially accessories) that are used only partially.
“don’t worry about creating a spread sheet when it’s already been done”
Snapshot of my spreadsheet for the purchases in December 2010:
The numbers in the far left column is the “identity number” so the month starts out with
1768 kits already in the stash and ends with 1789.
I found out about Scalemates some years later and by then I had no intention whatsoever
of copying, possibly restructuring to fit their layout, to Scalemates.
I like ScaleMates for the reference service it provides. However, I’ve always kept my data in a local spreadsheet where I have full control. 
—mike
I make sure my stash is manageable by hand. I want to be sure I get to build all that I buy…
To funny but true also for me 
sort off
I mange a part of the stash (only kits, i never came round do do the rest) in Scalemates as it’s helpful to find the appropriate decals, resin, PE. But i have the excel file with the kits paints and appropriate PE taps